There were none available, but I generated MD5 checksum lists which are hosted on Github for now. There is a checksum file for each AHN3 product:
In theory these checksums are not going to change anymore, the AHN3 is complete since the last update (last month). We are currently working on moving the AHN3 download service to the cloud, adding checksums is now part of the migration plan. Thanks for bringing this to our attention!