SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '661c8ee5b83da31834998713cefe05c26fcb0fa68b5aadf9fdb4cdb1fb0b6253' 
  AND token = '6wp/ULZeoCa1NQBDcm9p5UXq49Ij1x5Gv7+JAXMweVg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

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