Exclude Product From Discount Coupons in WooCommerce

/**

* Snippet Name: Exclude Product From Discount Coupons.

*/

add_filter( 'woocommerce_coupon_is_valid_for_product', 'exclude_product_from_product_promotions', 999, 4 );

function exclude_product_from_product_promotions( $valid, $product, $coupon, $values ) {

   // Product id here (i.e. 123)

   if ( 123 == $product->get_id() ) {

      $valid = false;

   }

   return $valid;

}