How many minutes will it take for a 125 pound person to use 198 calories?

If you're on a treadmill, walking/jogging at about 3 mph, it will take 40-60 minutes.

The less body fat you have, the harder it is to lose it. I'm 140 lbs, and it takes me roughly twenty minutes to walk a mile on a treadmill (with high incline) at 3.2 mph, and for every mile I walk, I burn 100 calories. So it takes me twice as long to burn 200.

Taking into account your smaller weight and therefore (probably) smaller fat percentage, it'll take you anywhere up to half a mile more to burn as many calories.