How to add 2 hours to the wordpress time formed with current_time(“mysql”, false)?

The WordPress current_time() returns the current time in the format specified in the first parameter. In your example code, this is the mysql value. The second parameter represents a timezone option. The default returns the local time for the timezone specified on the site’s Settings > General page, or GMT depending on the value supplied when calling the function.

https://codex.wordpress.org/Function_Reference/current_time

If time mathematics are still required, using the PHP strtotime() function is useful for this:

$now = current_time( 'mysql' ); 
echo 'It is currently: ' . $now . '<br>';
$later = date( 'Y-m-d H:i:s', strtotime( $now ) + 7200 ); //7200 seconds = 2 hours
echo 'In 2 hours it will be: ' . $later;