Hi, I have fixed the problem. I am posting content for others to use.
Your plugin caches comments, which is why our code does not work. Also, after writing the filter, it is necessary to activate and deactivate the plugin once. The problem was solved by adding the following line of code.

add_action('pre_get_comments', function ($query)
{
    $query->query_vars = [
        [
            'key' => 'keyurl',
            'value' => "http://$_SERVER$_SERVER"
        ]
    ];
}, 10, 1);

Thank you very much for your answer
I tested this code but it does not work. All comments are displayed!

Please use this code: 

add_action('pre_get_comments', function ($queryObj) {
            $vars = $queryObj->query_vars;
            $vars = 'keytoopurl';
            $vars = 'y';
            $queryObj->query_vars = $vars;
    });

Hello asti and thank you very much for your answer
I am a developer.

I get the comment with the  get_comments() function and I want wpdiscuz to show only the comments I received. How can I do this?  Please provide me with a sample code 

my sample code:

    $comments20 = get_comments (array ('meta_key'=> 'keytoopurl', 'meta_value'=> 'y'));

I want wpdiscuz to display only variable  comments20 

How can I do this?

Thanks for your cooperation

If you're a developers you can use the get_comments() and get_comment() functions. 

Also, we have plugin customization and custom addon development services at the gVectors Team. They can assess the work and create it for you. Just contact us via salesgvectors.com email address and send a list of requirements you'd like to have.