If the delivery is not in the normal area and 10 miles away, the driver made a special trip for you. That is 20 miles to and from your business, or about one gallon of gas at $4/gallon. Chances are, you were the only stop I that 30+ minutes he was on the road.
Subtract his gas costs and it is a $6 tip, provided it was a $25 bill and the tip was $10.
I think if your business wants them to deliver again, you might have to at least ante up gas money on top of a tip in order to make it worth the driver's while to go7 miles outside of his normal delivery range.
FWIW.....45 min is not a long time, especially if you consider the distance they have to drive and cook the food too.