Bomb defusal

You are a secret agent trying to defuse a bomb.

The bomb detonates 46 seconds after the lightbulb turns on. You can only stop it by pressing a button a second before the explosion. Pressing the button sooner or not at all will detonate the bomb.

You don't have a watch with you, just a lighter and two fuzes. Each of the fuzes burns for exactly one minute, but they do not burn evenly.

Some parts of the cord may burn faster...

... others more slowly.

This means that half of each fuse does not necessarily burn for 30 seconds, it can burn faster or slower.

Using fuzes and a lighter, how can you tell when exactly 45 seconds have passed since the light was turned on?