WooCommerce Add to Cart Redirect to Checkout for one product

add_filter( 'woocommerce_add_to_cart_redirect', 'misha_skip_cart_redirect_checkout' );

function misha_skip_cart_redirect_checkout( $url ) {
    $product_id = 33; // Die Produkt-ID, für die der Checkout aktiviert werden soll

    $cart = WC()->cart;
    $cart_items = $cart->get_cart();

    foreach ( $cart_items as $cart_item_key => $cart_item ) {
        if ( $cart_item['product_id'] == $product_id ) {
            $url = wc_get_checkout_url();
            break;
        }
    }

    return $url;
}