Absolutely yes. Even though these protein powders are derived from grains and legumes (food groups which are restricted on the keto diet), most of the starch/carb content has been removed. Growing Naturals rice protein and pea protein are considered very low carb with less than 4g per serving (depending on the flavor), so they are ideal for use as rich protein sources in the keto diet. Other off-brand plant protein powders should be evaluated for the carb content to make sure it is ok to use on the keto diet.
For more info please check out “Eating the Right Protein on the Ketogenic Diet“