The optimization process and recommendations:

1. Avoid Subqueries (query line: 7): We advise against using subqueries as they are not optimized well by the optimizer. Therefore, it's recommended to join a newly created temporary table that holds the data, which also includes the relevant search index.
2. 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.
3. Sort and Limit Before Joining (modified query below): In cases where the joins aren't filtering any rows, it's possible to sort and limit the amount of rows using a subquery in the FROM clause, before applying the joins to all other tables.

Optimal indexes for this query:

ALTER TABLE `pg_show` ADD INDEX `pg_show_idx_url` (`url`);

The optimized query:

SELECT
        pg_show_php,
        pg_show_tab,
        pg_text.text AS title,
        pg_text.text AS description 
    FROM
        (SELECT
            pg_show.php AS pg_show_php,
            pg_show.tab AS pg_show_tab,
            pg_show.tit AS pg_show_tit,
            pg_show.desc AS pg_show_desc 
        FROM
            pg_show 
        WHERE
            pg_show.url = 'value' LIMIT 1) AS pg_show 
    INNER JOIN
        pg_text 
            ON pg_show.pg_show_tit = title 
    INNER JOIN
        pg_text 
            ON pg_show.pg_show_desc = description 
    WHERE
        1 = 1 LIMIT 1