SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12f14ee459cc28bb0384bb21670a0b20cf8f7525087948e09cedfd04f8dad1f3' 
  AND token = 'ZqLLl6tyv1o3Bj+GtJ8eHlXhlPQ6QD9Hve4pWrfUnIs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

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