Using wpdb without loading all plug-ins via wp-load.php
I'm trying to prevent WP from loading all plug-ins when including wp-load.php, since I don't really need them nor the usual WP actions/filters. All I need is the WPDB class to query the database easily.
I've only found an (old) solution that involves defining WP_INSTALLING to trick WP into not loading plug-ins, but I'm not sure if it still works on current versions and/or if there's a better way.
(Background: I'm trying to optimize a simple autocomplete PHP script that serves JSON results via AJAX by doing some simple queries after initializing $wpdb via wp-load.php)