SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ad6e490e94943192f8cdca32ab02a6efb092e354051613ac33f5edddb2f48f4' 
  AND token = 'VMFR1pttnCt7osHe6cmm6MPZiDvNLA9NRnZOhqHb0dA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}