High Usage / Query of SQL

On one of the sites I support we are seeing an increase in traffic and getting reports that the sql query from the plugin is running 40 times per house

SELECT g.ID FROM owf_posts g WHERE g.post_type = "tsml_group" AND (SELECT COUNT(*) FROM owf_postmeta m WHERE m.meta_key="group_id" AND m.meta_value = g.id) = 0;

I’m not sure if there is anything we can do or if this content can be moved outside the posts / postmeta to improve performance