Unknown Anisong, sung by Hori Kyouko in Horimiya episode 2
Edit: okay, turn out I found the song. Here it is. It's the theme song of Hurricane Star, a fictitious anime in the Horimiya universe. In the webcomic, the title of the anime is "魔神戦機天使隊ハリケーンスター". They managed to compose the song for the joke reference to the manga and add it to the anime album song.