im a beginner with PHP, so i hope that someone can help me solving this issue.

I want to display the expiration date of a post with the following plugin https://wordpress.org/plugins/advanced-schedule-posts/

I’ve think i can use:
$hasp_expire_date = get_post_meta( $post_id, ‘hasp_expire_date’, true );

But i don’t know how to insert it into a php file. I need to place in this code (Where it says CODE HERE):

                $num_comments = get_comments_number( $block_data['id'] );
                $entry_comments = 'CODE HERE<i class="fa fa-speech-bubble"></i><span>'.$num_comments.' '._nx( 'Comment', 'Comments', $num_comments, 'comments', 'uncode' ).'</span>';