Are there carbs in crown royal whiskey?

The general answer is No - there are no carbs in Whiskey. At a broader level, any distilled liquor will have low, if any, carbs. This would include Whiskey, Rum, Vodka, Gin, etc.

There are exceptions, however. Typically these include the liquors to which additional flavoring has been added. Some examples would be Capt. Morgan's Spiced Rum and Bacardi Vanilla.

Finally, be sure to check any mixers you intend to use with the liquor. Vodka may have 0 carbs, but regular tonic water can have quite a few (approx. 15g/serving). Diet Tonic, on the other hand, will have none.