search for established connections over 1 hours old with 40 B size

We have a lot of established connections on our Mikrotik-router that are x hours old, with 40B size. Is there a way to kill all connections older than x hours old, with org bytes = 40 ?

bump..

/ip firewall connection remove [find where orig-bytes=40 and _____ ]

Someone else is going to have to help on the time thing - something about the behavior of the times in connection tracking still makes me scratch my head.