Are there any certified pre-owned Lexus ES models available near Los Angeles?

My car literally broke down on the 405 yesterday and I am so done with it. I really want a Lexus ES because they look so nice but my budget is only like $35,000 max. My friend told me I should look for something called certified pre-owned or CPO but honestly I have no idea what that actually is or how it works. Is it just a used car? I live near Northridge and I need a new ride by next Friday for work. Sorry if this is a total newbie question but does anyone know if there are any of those certified ES models actually sitting on lots near LA right now? I dont even know which dealerships to call...