I am not a lawyer but I do know that the constitution forbids exorbitant sentencing. I was in error stating that his conviction would be overturned - but the sentence was what I had in mind, and that based upon the eighth amendment.
The 8th amendment forbids cruel and unusual punishments. It also forbids excessive fines. That did not prevent a judge in Oregon from imposing a fine well over $100,000 on the owner of a bakery for offending the feelings of a homosexual couple.