Hello,
You can disable AJAX “Add To Cart” in Theme Options > E-Commerce > Single Product Page.
To change the link – copy etheme_enqueue_scripts function from wp-content/themes/classico/framework/theme-init.php into functions.php of your child theme > change
$etConf['checkoutUrl'] = esc_url( wc_get_checkout_url() );
to
$etConf['checkoutUrl'] = esc_url( wc_get_cart_url() );
Regards