I do fly out of MCI almost weekly. If you're not checking a bag, arriving 30min. ahead of departure often works, so long as you know where you're going in the terminal so you end up at the right security checkpoint for your gate, and in fact I did that a couple weeks ago because I overslept.

I still personally prefer to show up an hour ahead in order to not feel rushed (which happens if I go straight from security to boarding), though, and in case of delays or other stuff that'd require multiple trips in/out of secure area.