mysql.slow.log shows smtp_poplocks

[tkalfaoglu]

my mysql slow queries log file shows:
SET timestamp=1169471897;
delete from smtp_poplocks where ((lock_time < DATE_SUB(NOW(), INTERVAL 30 MINUTE)) and (lock_time IS NOT NULL));
# User@Host: admin[admin] @ localhost []
# Query_time: 19 Lock_time: 0 Rows_sent: 0 Rows_examined: 0
SET timestamp=1169471897;
delete from smtp_poplocks where ((lock_time < DATE_SUB(NOW(), INTERVAL 30 MINUTE)) and (lock_time IS NOT NULL));
# User@Host: admin[admin] @ localhost []
# Query_time: 18 Lock_time: 0 Rows_sent: 0 Rows_examined: 0
SET timestamp=1169471897;
delete from smtp_poplocks where ((lock_time < DATE_SUB(NOW(), INTERVAL 30 MINUTE)) and (lock_time IS NOT NULL));

Should I run an optimize, or try to create an index for this table??

Thanks!
-turgut