One thing that happens in the Super Speedy Search settings page is we figure out what unique post_meta keys you have. If you have a huge wp_postmeta table then this may cause the settings page to timeout.

Some users may have thousands of meta_keys and it may be tricky to actually navigate through the entire list.

In both of these cases, you can bypass our SELECT DISTINCT meta_key query by telling us in your functions.php file which meta keys to show. We do cache the result of this SELECT DISTINCT query, but if you are running regular imports your cache may be getting wiped, or your timeout settings may be so low that it doesn’t get a chance to cache the result in the first place. Or you may just want to restrict how many meta keys to show to have a cleaner interface.

Choose your meta keys for Super Speedy Search settings in your functions.php

In your child theme functions.php file, add the following code:

add_filter('pre_sss_meta_keys', function() {
    return ['_sku', 'external_image'];
});