Slow query log

[charlesr]

# Query_time: 36 Lock_time: 0 Rows_sent: 10 Rows_examined: 9670
SELECT post.postid, post.attach
FROM post AS post

WHERE post.threadid = 31776
AND post.visible = 1
AND post.userid NOT IN (3472,11,4180)

ORDER BY post.dateline
LIMIT 9660, 10;


Seems like a lot of rows examined. Is there an index problem with this query?

If there is, how do I go about tracking it down?