Yes, there is a DFP available for the MAX32660. It can be found at the following link*:
http://www.keil.com/dd2/maxim/max32660/
To use the MAX32660-EVSYS with the Keil IDE, you will need to change the debugger. In Keil, go to Flash > Configure Flash Tools > Debug. In the top right corner, change the debugger to CMSIS-DAP Debugger.
* Link valid as of April 2019