I have a 39-year-old bike, locked with a $100 lock - the Kryptonite chain and small U-lock. The rear wheel has its own separate lock, and the seat is attached with a length of old bicycle chain. I carry the locks in the basket. You have a basket, right?
The main lock would take over 10 minutes to cut with an electric cutter. The lock is not one of the ones you can pick with a pen.
I live in New York City. This method has never failed me.