Time oriented operations are generally considered outside the realm of what a database does, and should generally be handled by a cron job.
It's pretty simple. Put a creation timestamp field into your table, then every 5 minutes or so, run a cron job that deletes rows that are >1 hour old. i.e.
$now = time();
delete from table where tstamp<'($now-86400)'
kinda thing (not sure that's the correct syntax, but you get the idea.)