The optimization process and recommendations:

1. Avoid OFFSET In LIMIT Clause (query line: 37): OFFSET clauses can be very slow when used with high offsets (e.g. with high page numbers when implementing paging). Instead, use the following \u003ca target\u003d"_blank" href\u003d"http://www.eversql.com/faster-pagination-in-mysql-why-order-by-with-limit-and-offset-is-slow/"\u003eseek method\u003c/a\u003e, which provides better and more stable response rates.
2. Avoid Regular Expression Filtering (query line: 32): When a regular expression filtering is applied on an indexed column, the database's optimizer won’t be able to use the index. Consider replacing this call with an alternative condition that won’t use a regular expression.
3. Avoid Regular Expression Filtering (query line: 33): When a regular expression filtering is applied on an indexed column, the database's optimizer won’t be able to use the index. Consider replacing this call with an alternative condition that won’t use a regular expression.

The optimized query:

SELECT
        post.id,
        short_story,
        SUBSTRING(full_story,
        1,
        15) AS full_story,
        xfields,
        title,
        category,
        alt_name,
        comm_num,
        allow_comm,
        allow_rate,
        FIXED,
        rating,
        vote_num,
        news_read,
        votes,
        editdate,
        editor,
        reason,
        view_edit,
        tags 
    FROM
        post 
    LEFT JOIN
        post_plus 
            ON (
                post.id = post_plus.news_id
            ) 
    WHERE
        category REGEXP '[[:<:]](130|3|4|5|6|7|8|9|10|11|12|13|14|15|16|17|18|19|21|22|24|25|26|27|29|133|135|125|20|132)[[:>:]]' 
        AND category REGEXP '[[:<:]](73)[[:>:]]' 
        AND approve = 1 
    ORDER BY
        FIXED DESC,
        DATE DESC LIMIT 98,
        7