The optimization process and recommendations:

1. Avoid Calling Functions With Indexed Columns (query line: 58): When a function is used directly on an indexed column, the database's optimizer won’t be able to use the index. For example, if the column `jobtitle` is indexed, the index won’t be used as it’s wrapped with the function `LOWER`. If you can’t find an alternative condition that won’t use a function call, a possible solution is to store the required value in a new indexed column.
2. Avoid Calling Functions With Indexed Columns (query line: 59): When a function is used directly on an indexed column, the database's optimizer won’t be able to use the index. For example, if the column `jobmaincategory` is indexed, the index won’t be used as it’s wrapped with the function `LOWER`. If you can’t find an alternative condition that won’t use a function call, a possible solution is to store the required value in a new indexed column.
3. Avoid Calling Functions With Indexed Columns (query line: 60): When a function is used directly on an indexed column, the database's optimizer won’t be able to use the index. For example, if the column `jobsubcategory` is indexed, the index won’t be used as it’s wrapped with the function `LOWER`. If you can’t find an alternative condition that won’t use a function call, a possible solution is to store the required value in a new indexed column.
4. Avoid Calling Functions With Indexed Columns (query line: 61): When a function is used directly on an indexed column, the database's optimizer won’t be able to use the index. For example, if the column `jobdescription` is indexed, the index won’t be used as it’s wrapped with the function `LOWER`. If you can’t find an alternative condition that won’t use a function call, a possible solution is to store the required value in a new indexed column.
5. Avoid Calling Functions With Indexed Columns (query line: 62): When a function is used directly on an indexed column, the database's optimizer won’t be able to use the index. For example, if the column `jobcountry` is indexed, the index won’t be used as it’s wrapped with the function `LOWER`. If you can’t find an alternative condition that won’t use a function call, a possible solution is to store the required value in a new indexed column.
6. Avoid LIKE Searches With Leading Wildcard (query line: 58): The database will not use an index when using like searches with a leading wildcard (e.g. '%taxi%'). Although it's not always a satisfactory solution, please consider using prefix-match LIKE patterns (e.g. 'TERM%').
7. Avoid LIKE Searches With Leading Wildcard (query line: 59): The database will not use an index when using like searches with a leading wildcard (e.g. '%taxi%'). Although it's not always a satisfactory solution, please consider using prefix-match LIKE patterns (e.g. 'TERM%').
8. Avoid LIKE Searches With Leading Wildcard (query line: 60): The database will not use an index when using like searches with a leading wildcard (e.g. '%taxi%'). Although it's not always a satisfactory solution, please consider using prefix-match LIKE patterns (e.g. 'TERM%').
9. Avoid LIKE Searches With Leading Wildcard (query line: 61): The database will not use an index when using like searches with a leading wildcard (e.g. '%taxi%'). Although it's not always a satisfactory solution, please consider using prefix-match LIKE patterns (e.g. 'TERM%').
10. Avoid LIKE Searches With Leading Wildcard (query line: 62): The database will not use an index when using like searches with a leading wildcard (e.g. '%taxi%'). Although it's not always a satisfactory solution, please consider using prefix-match LIKE patterns (e.g. 'TERM%').
11. Avoid OR Conditions By Using UNION (modified query below): In mosts cases, filtering using the OR operator cannot be applied using indexes. A more optimized alternative will be to split the query to two parts combined with a UNION clause, while each query holds one part of the original OR condition.
12. Create Optimal Indexes (modified query below): The recommended indexes are an integral part of this optimization effort and should be created before testing the execution duration of the optimized query.
13. Use UNION ALL instead of UNION (query line: 48): Always use UNION ALL unless you need to eliminate duplicate records. By using UNION ALL, you'll avoid the expensive distinct operation the database applies when using a UNION clause.

Optimal indexes for this query:

ALTER TABLE `job` ADD INDEX `job_idx_jobbusi_jobfixe_jobfixe_jobendd` (`jobbusiness`,`jobfixedstartdate`,`jobfixedenddate`,`jobenddate`);
ALTER TABLE `job` ADD INDEX `job_idx_jobbusi_jobfixe_jobfixe_jobstar` (`jobbusiness`,`jobfixedstartdate`,`jobfixedenddate`,`jobstartdate`);
ALTER TABLE `job` ADD INDEX `job_idx_jobbusi_jobfixe_jobfixe_jobdate` (`jobbusiness`,`jobfixedstartdate`,`jobfixedenddate`,`jobdateadded`);
ALTER TABLE `job` ADD INDEX `job_idx_jobdele_jobpaye_jobbusi_jobstar` (`jobdeleted`,`jobpayed`,`jobbusiness`,`jobstartdate`);

The optimized query:

SELECT
        job_jobunique,
        job_jobtypeunique,
        job_joblat,
        job_joblng 
    FROM
        ((SELECT
            job.jobunique AS job_jobunique,
            job.jobtypeunique AS job_jobtypeunique,
            job.joblat AS job_joblat,
            job.joblng AS job_joblng 
        FROM
            job 
        WHERE
            (
                job.jobbusiness = 0 
                AND job.jobfixedstartdate = 1 
                AND job.jobfixedenddate = 1 
                AND job.jobenddate <= CURDATE()
            )) 
    UNION
    DISTINCT (SELECT
        job.jobunique AS job_jobunique,
        job.jobtypeunique AS job_jobtypeunique,
        job.joblat AS job_joblat,
        job.joblng AS job_joblng 
    FROM
        job 
    WHERE
        (job.jobbusiness = 0 
        AND job.jobfixedstartdate = 1 
        AND job.jobfixedenddate = 0 
        AND job.jobstartdate >= CURDATE())) 
UNION
DISTINCT (SELECT
    job.jobunique AS job_jobunique,
    job.jobtypeunique AS job_jobtypeunique,
    job.joblat AS job_joblat,
    job.joblng AS job_joblng 
FROM
    job 
WHERE
    (job.jobbusiness = 0 
    AND job.jobfixedstartdate = 0 
    AND job.jobfixedenddate = 0 
    AND job.jobdateadded >= (CURDATE() - INTERVAL 60 DAY))) 
UNION
DISTINCT (SELECT
job.jobunique AS job_jobunique,
job.jobtypeunique AS job_jobtypeunique,
job.joblat AS job_joblat,
job.joblng AS job_joblng 
FROM
job 
WHERE
job.jobdeleted = 0 
AND job.jobpayed = 1 
AND (LOWER(job.jobtitle) LIKE '%taxi%' 
OR LOWER(job.jobmaincategory) LIKE '%taxi%' 
OR LOWER(job.jobsubcategory) LIKE '%taxi%' 
OR LOWER(job.jobdescription) LIKE '%taxi%' 
OR LOWER(job.jobcountry) LIKE '%taxi%') 
AND (job.jobbusiness = 1 
AND job.jobstartdate <= CURDATE() 
AND job.jobenddate >= CURDATE()))
) AS union1