Thank you for reaching out to the Support Community and great question!
The SMS code expires by default in 5 minutes once the code has been sent to the device. Unfortunately, the timeout is not configurable at this time.
I do not currently see this feature on our product roadmap, however, if you do wish to see this feature available in the future I would recommend submitting a feature request. The best way to file feature requests would be from the community site. I have outlined the steps below:
Go to support.okta.com
Click on "Community" in the center of the screen
Scroll down to the section titled "Make a Feature Request," click the "Go to Ideas" button.
Enter your tenant name and click "Go"
Sign in and submit the feature request.
Once feature requests are submitted they are visible to other Okta admins, who can vote on them to provide more visibility. Using this method will allow you to maintain visibility on your feature requests throughout the process.
Aleks Bulajic Technical Support Engineer Okta Global Customer Care