No, the Photon only supports microSDHC, and like you said, the 64gb (also, anything over 32gb) is classified as microSDXC.
32gb + 16gb internal should be more than enough anyways, provided you use it wisely.
If you absolutely NEED that amount of space, some users were able to use the Photon as a USB host and attach an external USB flash stick using a special USB-F-MicroUSB-M
Samsung Galaxy S III T999v running stock on Virgin Mobile Canada
Motorola Photon running CyanogenMod 7.2 on Virgin Mobile Canada [traded for S3]