How to hide the author box of a specific user?

If you know the data of the author, you can wrap that box with an if and the function get_the_author

if( get_the_author() == "name_of_the_author" ){
// Don't do it
}else{
// Print box
}

EDIT with the final answer updated:

<?php echo $td_mod_single->get_social_sharing_bottom();?>
<?php echo $td_mod_single->get_next_prev_posts();?>
<?php
 $user = get_user_by("login", "pknn"); // user object
 // get_the_author() needs the display name, not the login
 if( get_the_author() != $user->data->display_name ){
  echo $td_mod_single->get_author_box();
 }
?>
<?php echo $td_mod_single->get_item_scope_meta();?>