Add 'Buy Now' button to WooCommerce Single Product Page

buy-now.php

function custom_wc_add_buy_now_button_single_before() {
    echo '<div id="cart-action-wrapper">';
}
add_action( 'woocommerce_before_add_to_cart_button', 'custom_wc_add_buy_now_button_single_before' );
function custom_wc_add_buy_now_button_single_after()
{
	global $product;
    $current_product_id = get_the_ID();
    $product = wc_get_product( $current_product_id );
    $checkout_url = WC()->cart->get_checkout_url();
    if( $product->is_type( 'simple' ) ){
        echo '<a href="'.$checkout_url.'?add-to-cart='.$current_product_id.'" class="buy-now button">Buy Now</a></div>';
    }
}
add_action( 'woocommerce_after_add_to_cart_button', 'custom_wc_add_buy_now_button_single_after' );

buy-now.scss

$primary-color: #39ba78;
$button-hover-color: #3a3a3a;

#cart-action-wrapper {
    align-items: flex-start;
    display: flex;

    .single_add_to_cart_button {
        border: 1px solid $primary-color;

        &:hover {
            border-color: $button-hover-color;
        }
    }

    .buy-now {
        background-color: #fff;
        border: 1px solid $primary-color;
        color: $primary-color;
        line-height: 1em;
        margin-left: 1em;
        padding: 10px 20px;

        &:hover {
            background-color: $primary-color;
            color: #fff;
        }
    }
}

@media (max-width: 479.98px) {
    #cart-action-wrapper {
        flex-direction: column;

        .buy-now {
            margin: 0 0 1em 0;
        }
    }
}