When you have AMP pages in the Google AMP cache you should link directly to them from your Ads and other places in order to take advantage of the (almost) instant page delivery available.
How do you find them?
This is a regular web page, built to AMP standards
Query the AMP Project for the URL of the cached page
This is the direct URL for cached AMP page. It will show in the address bar after you query the AMP project