sklearn.model_selection: GridSearchCV vs. KFold
Yes, you can replace the cv=5 with cv=KFold(n_splits=5, random_state=None, shuffle=False). Leaving it set to an integer, like 5, is the equivalent of setting it to either KFold(n_splits=5) or StratifiedKFold(n_splits=5), depending on the model you pass to the estimator parameter of GridSearchCV()