If the top drawer of your workbench doesn’t have a lock and you want to discourage young hildren from opening it, consider this idea.
On the surface of the bench, mark a point just inside the drawer back. At the marked point, drill a counterbored hole to accept a 5/16-inch or 3/8-inch diameter bolt. Make the counterbore just deep enough to allow the bolt head to rest slightly below the surface of the bench (a washer under the bolt head is also a good idea).
To secure the drawer just close it up and drop the bolt into the counterbored hole. To release it, use a pair of needle-nose pliers (or a magnet) to remove the bolt.
Upper Jay, NY