SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c765cdf45f2e4d6fcac696e0e08f8555e32c7c2dc547425d981cd352c43ef73e' 
  AND token = '6su5hCFAwC+is8RxHXRBeyWALtzUk3k0YNxvXrOREKE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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