MR Fingerprinting can be used for a fast and quantitative estimation of physical parameters in MRI. For the fast acquisition of MRF, common approaches have used non-Cartesian sampling of k-space. Here, we introduce a method for non-iterative anti-aliasing of the spiral MRF time series, based on the concept of keyhole imaging. Our approach does not change acquisition or dictionary creation and matching procedures. As frames require only minimal density compensation in k-space, noise amplification during reconstruction is reduced. After applying our algorithm, individual images from the MRF time series are artifact-free and clearer parameter maps are obtained in a shorter time while preserving the accurate quantification of MRF.