SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cfea82aa15f8ad8d0df2fc944553303c8bb6e553f13fddf01bddd019b936d48' 
  AND token = 'khIJtnV2+HpcaPa2a0RTCOy3O7E8rgTAn6Rb65d+HWA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

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