About 30 seconds later, it was unlocked.
I used that lock for about 10 years, until I went to University, where the thieves were a bit smarter.
Many bike posts in my university's undercover bike shed often had several locks without a bike in sight. It turned out many people leaving bike locks on posts they often use (it doesn't take up much space or prevent someone from using the post).
It saves those cyclists the hassle of carrying the the lock with them (only the key), which is particularly an issue with those very heavy bike U-locks and D-locks.
My cherished (and uber low grade) bike was stolen in Paris. The robber didn't bother to find the code, they ripped that tiny cable apart. They were nice enough to leave the bits in a McDonald's bag where the bike was attached (and of course, the McDonald's was just in front of me). Anyway I know have a 2kg keylock chain on my new bike.