Listen to Restful Keys of Calm online. Restful Keys of Calm is an Unknown language song and is sung by 963 Hz Solfeggio Tones, Sleep Music for You and Sleep Music 101. Restful Keys of Calm, from the album Lofi Sleep Rhythms: Melodies for Soothing Nights, was released in the year 2025. The duration of the song is 3:53. Download Unknown songs online from JioSaavn.