How cache works on WooCart
WooCart cache is built for each country and each browser separately. This is to correctly serve multi-language and multi-currency stores without issues. The first load for the country or browser is slower, but every next load is served from cache. The cache is flushed every hour.
When you are testing on the mywoocart.com subdomain, your store might feel slow if you're the first visitor for the country or browser. When the store is live, this is not an issue since the cache is quickly built by live visitors.
Image/CSS CDN Cache
If you changed images or your CSS is not refreshing with regular Flush Cache, you need to Flush CDN Cache as well. Go to Addons > KeyCDN and click the link. Clearing CDN cache can take up to 10 minutes.