MySQL queries optimization

Hi. I use the old version of this plugin (8.4)

Slow query causes the server to crash.
Example

# Query_time: 5.251648  Lock_time: 0.000346 Rows_sent: 2  Rows_examined: 199189
SET timestamp=1595970481;
SELECT   trade_posts.ID FROM trade_posts  LEFT JOIN trade_postmeta ON ( trade_posts.ID = trade_postmeta.post_id )  LEFT JOIN trade_postmeta AS mt1 ON (trade_posts.ID = mt1.post_id AND mt1.meta_key = '_fep_delete_by_1' )  LEFT JOIN trade_postmeta AS mt2 ON (trade_posts.ID = mt2.post_id AND mt2.meta_key = '_fep_parent_read_by_1' ) WHERE 1=1  AND trade_posts.post_parent = 0  AND ( 
  ( trade_postmeta.meta_key = '_fep_participants' AND trade_postmeta.meta_value = '1' ) 
  AND 
  mt1.post_id IS NULL 
  AND 
  mt2.post_id IS NULL
) AND trade_posts.post_type = 'fep_message' AND ((trade_posts.post_status = 'publish')) GROUP BY trade_posts.ID ORDER BY trade_posts.post_date DESC;

What is the solution to this problem?

Thank you for help.