SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8573a0be9be9c4580d827fd97b5cfefe5e976a471f0e08f978c8b35a3cbaf8c0' 
  AND token = '7DQqveIJZTGldSoc2V6q1QEF3dO3cSzPrFE+5V6ynF4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Impossible WHERE noticed after reading const tables