SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe63331027922807c2204199562cecf5d8b12fde48fe6c68b65efc434c06376f' 
  AND token = 'jEeN7UJFUQJtLYKrJSKaksDzj4P+G8mJYZCP3hQGt/E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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