I want to know if it’s good for SEO [closed]

The /wp-admin/ajax.php file should not be locked – it is used to power all AJAX functionality on the site.

Your robots.txt file specifically instructs search engine spiders (like Google) to allow access to /wp-admin/ajax.php:

User-agent: *
Disallow: /wp-admin/
Allow: /wp-admin/admin-ajax.php

Sitemap: http://example.com/sitemap.xml

Either remove the Allow: /wp-admin/admin-ajax.php and keep /wp-admin/ locked (effectively disabling all AJAX functionality on your site) or – better solution – unlock /wp-admin/ and use the WordFence Security plugin.