Output expiry date coupon in PHP

I have code.

$couponargs = array(
    'post_type' => 'shop_coupon',
    'post__in' => $couponarrayfinal,
    'orderby' => 'title',
    'order' => 'ASC',
    'posts_per_page' => '-1'); 
$coupons = get_posts($couponargs);

<div class="wt-mycoupons">
   <ul>
    <?php
    foreach ($coupons as $coupon) {
        // if( $coupon->post_title == 'test-coupons' ) {

        // } else {

        // }

        echo "<li class='wt-single-coupon'><div class='title-coupon'>$coupon->post_title</div><div class='desc-coupon'>$coupon->post_excerpt</div></li>";
    }
    ?>
</ul>
</div>

How can I output date_expiry in my code? Because I can output the date of creat, but I need the expiry_date.

Thank you.