SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '973ff508c7a9c1302a933a9cbb5c1eea4f96727ae11e15768ab4159a64b9f448' 
  AND token = '9ur3CoNaFp8Q4XPGUjDJ7U20JnKW3+0UpEGc/FBUMvg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

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