Hello,
We have updated theme to the latest version, set all the possible speed optimization settings in our theme. Speed result is the following http://prntscr.com/vdxp6p https://tools.pingdom.com/#5d66003544000000
Read here about cart fragments and how to disable it if you decide to do this https://www.webnots.com/fix-slow-page-loading-with-woocommerce-wc-ajaxget_refreshed_fragments/
Regards