Tags cause a temporary table

[Bartosz.Misiak]

explain
SELECT t.tag_text, COUNT(t.tag_text) as times, t.tag_meta_app, t.tag_meta_area
                    FROM ipb_core_tags t WHERE  1=1
                    AND t.tag_aai_lookup IN( SELECT p.tag_perm_aai_lookup FROM ipb_core_tags_perms p WHERE
                 ( ( FIND_IN_SET(3,p.tag_perm_text) ) OR ( p.tag_perm_text='*' ) ) AND p.tag_perm_visible=1 ) GROUP BY t.tag_text
ORDER BY times DESC
LIMIT 0, 50

id select_type table type possible_keys key key_len ref rows Extra

1 PRIMARY t ALL tag_aai_lookup NULL NULL NULL 127920 Using temporary; Using filesort

1 PRIMARY p eq_ref tag_perm_aai_lookup,tag_lookup tag_perm_aai_lookup 96 t.tag_aai_lookup 1 Using where

Hello.

How do I stop this from happening in the future? It caused the load to skyrocket. I could, of course, increase tmp_table_size, but I'd like to know if there's something about optimizing IPB that I should be aware of. Am I missing some indexes?