[CB 5.1.1] Exact route match

I’m trying to have the following url:
http://appbaseurl/cat1

mapped to “main.cat1”, and this is the relevant code in Router.cfc:
route(“cat1”).to(“main.cat1”).end();
route(":handler/:action?").end();

This works, but it’s a “greedy” match, as it’s also mapping all the following to “main.cat1”:
http://appbaseurl/cat1/subcat1
http://appbaseurl/cat1/subcat2

http://appbaseurl/cat1/subcat1/subcat11

etc.

How do I change the mapping so that it only matches http://appbaseurl/cat1?