What do you want to change in the product layout?
Most of the stylings can be changed (for eg button, text, image) from woocommerce-style.css located inside the css folder (ie wp-content/themes/krystalpro/css/)
Ok, thank you. But I think I meant one of *.php template files. The one that will let me, for example, switch positions of “Add to cart” button and product description; or add something there.