Checkout Speedup For WooCommerce is the only plugin that can easily help you speed up your WooCommerce checkout.
Usually, the checkout powered by WooCommerce is slow because WooCommerce sends the transactional emails during the checkout, and WordPress loads all the plugins and the theme during the process.

With Checkout Speedup For WooCommerce, you can defer the transactional emails, and unload the theme and unneeded plugins during the checkout process.
The transactional emails will be sent immediately after the end of the checkout process, and not any more during the process.
You will find a settings page where you can unload the unneeded plugins and the theme during the checkout. Usually, you need only WooCommerce, and in some cases some add-ons of WooCommerce, not more.