If you can manage to go by U.P roadways bus,
Exit via second entry GT road side, Gandhi park bus stand is adjacent (400 meter ) to railway station.
Ask any e-rickshaw guy he will charge 10-20₹.
At Gandhi park bus stand you will find buses for mathura.
Some...
more... buses starts from bus stand it self. Service every 1 hr.
Or buses coming from Western UP takes passengers from road in front of bus stand.