SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd15d4ddf14feffb116ecfa3f92996e58f7c12cbdc5a1909f1f175973eedfaa23' 
  AND token = 'yPD65HLERf+h7EiEMon13g50ze21cC/sxA9FYNJOnRM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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