I need a new smartlock and it seems awfully difficult to find it clearly stated in the description if the lock supports a configurable time period for each key code when it will be active. What models support all of these features?
- Ability to program codes remotely over the Internet.
- Being able to set a time period when each key code will be active.
- Preferably no hub accessory needed or it should be compatible with a SmartThings hub or Alexa.
We have a Schlage Encode. It has all the features you’re looking for. Works well for us!
Does the Schlage integrate with Airbnb? I think it does.
I use the August lock, which does 1 and 3, not sure about 2, haven’t needed that. August integrates with Airbnb to give each Airbnb a new code that activates one hour before check-in time.
Might also want to check out this thread: Smart Lock-which one is best?
This is two years old. They like Schlage too: THE BEST Smart Lock for Airbnb & Vacation Rentals 
The Schlage Encode has all of those capabilities. I have four of them (three listings I manage and one in my home). If anything ever goes wrong with one of the locks, Schlage is quick to send a new lock, free of charge.
The august lock does what you are describing.
In the article I cited Schlage was #1 and August #2. I have August and have been happy with it.