How to run python script based on user input timer in php/mysql

Currently built a website that contain field for user to input number in time format. This input goes into mysql database when button is clicked.
I'm currently looking into how I can use this value insert by user and use it as timer to execute a python script, the python script is motor.py which will spin the motor, how can I make it work similar to cronjob. I have tried many different crontab web interface but they do not work as I would like it too. Is there any ways of achieving this? Thank You