Xiaomi (Mi, Redmi) MIUI phone users can manage screen lock time using the lock screen “Sleep” setting. This post gives a guide to manage lock screen sleep setting.
If you want to stay your Xiaomi phone screen stay on for longer time and stop quick auto screen lock, then change following setting.
To change or increase or disable screen lock time on a Xiaomi phone, open the “Sleep” setting from “Settings / Lock screen / Sleep” and set sleep time for screen lock. You can set sleep time in seconds or in minutes. And to disable auto screen lock, you can set the “Never” option.