SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f358552ecf1a887b66e44fa98fa1429ae66f4571cecf654363eca12998c796a' 
  AND token = '8mAZjXwGQRvblzzXMZdon0qTQMFJrKbqRsj4irDx4I8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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