What's your reason? You can just turn off the lockscreen (or at least I assume you have that option).
I'm using a feature called Trusted Bluetooth Devices on my Moto X. Basically, when you're connected to a trusted device like say a Pebble watch, it'll bypass any secure lockscreen you have enabled. And when you're out of range or disconnected, the secure lockscreen resumes.
I use that Screen Off and Lock app to turn my screen off via a Nova Launcher gesture (double tap) instead of pressing the power button. The problem is that it also locks my phone and overrides the trusted device feature so the next time I turn my screen on, I still have to enter my PIN to unlock it. If I just hit the power button, it does not lock it and the trusted device works as intended.
So I'm looking for a similar app that turns the screen off but does NOT lock it. I hope that's not too confusing.