Directions: In place of the long string at the end after "&" replace with {{gantry.token}} 
 
Example:
index.php?option=com_gantry5&view=configurations/15/layout&theme=rt_clarity&80078ed2583b0cc4c401a8d39860ed31=1
becomes...
index.php?option=com_gantry5&view=configurations/15/layout&theme=rt_clarity&{{gantry.token}}