Given production URL, display code otherwise don't.

display-if-production.php

<?php
  /**
   * Comparison adds script if site URL is same as production URL
   *
   * @returns inline script
   */

  $site_url = get_site_url();
  $prod_url = 'add-prod-url.com';

  if ( $site_url === $prod_url ) {   ?>

  // this was Google Analytics script but could be anything

  <script async src="..."></script>
    <script>
      window.dataLayer = window.dataLayer || [];
      function gtag(){dataLayer.push(arguments);}
      gtag('js', new Date());

      gtag('config', 'UA-671633-51');
    </script>

  <?php
  }     ?>