How to tune search argument in WP_Query to show only exactly the same results?

How to tune search argument in WP_Query to show only exactly the same
results?

Right now I am using this:
$args_search = array(
's' => $search,
'post_type' => array( 'post' )
);
$wp_query = new WP_Query( $args_search );
But the problem is that it shows everything.
E.g. if $search is just "2386" and I have in my db 3 posts:
"12386111" "23861111" "11112386"
I will get 3 results.
But I want to get 0 results. because it's not a full match.
Only if the search is 23861111 then I need to get the 1 result 23861111.
Or when it is 11112386 I need to type the full 11112386 as a $search
variable and not only 2386 or 238 to get the result 11112386
How to change my query to get the results as I want instead of everything
that contains the search string?