Shouldn't have to do that though! Never had to on my 5s
The 2nd gen Touch ID sensor in most of the latest models is super quick. I like not having as much hesitation but I agree that it can be a pain in the neck if you're just trying to look at notifications on your lock screen. While using a finger that isn't registered to Touch ID certainly isn't a perfect solution, it's the best solution I've found. Hopefully Apple figures something out in iOS 11.