It is technically in the format, it just doesn't have a slope which is why x isn't involved. Otherwise it would look weird to put y=0x+1 even though it would help to comprehend it.
Since y=1 does not have a slope because no x is found, this would be already written in the slope intercept form as y= 0x + 1
This would look like a horizontal line across the y intercept which in this case it would be 1
