SQL-DATABASE ERROR

Database error in WoltLab Burning Board (2.3.6): Invalid SQL: DELETE FROM bb1_adminsessions WHERE userid=0 AND lastactivity<1593780313
mysql error: Can't open file: './usr_web1_2/bb1_adminsessions.frm' (errno: 24)
mysql error number: 1016
mysql version: 5.5.47-0+deb6u1-log
php version: 5.3.3-7+squeeze29
Date: 03.07.2020 @ 15:45
Script: /board.php?boardid=33&page=1&daysprune=1000&sortfield=lastposttime&sortorder=ASC
Referer: