Is it permissible to trade a toy that includes music and things referred to as "magic" (such as producing fire or water from the hand and flying), on the condition that the buyer lowers their gaze and turns off the music?

If the music in games is unintentional and can be turned off, it does notharam the sale of the game. However, it is safer to avoid selling games that contain it. As for magic in games, selling a game is haram (definition) if it involves endorsing magic, glorifying it, or simulating the actions of sorcerers. However, fantastical elements or merely labeling something as magic without simulation do notharam its sale.