Hello,
As was shown on the videos from the previous reply, it is not slow. However, the ajax “add to cart” timeframe depends on your server and DB response time, not from our theme. So, to speed it up, contact your hosting provider and ask to reduce server response time, maybe check your DB structure.
In case you need professional help with site optimization you may contact WPKraken team, we don’t have optimization experts because that is outside the scope of our support.
Regards