if you want to search for a song:

    mpv --ytdl-format=bestaudio 'ytdl://ytsearch1:John Butler Trio Ocean'

As a function:

    !#/bin/bash

    yt(){
        mpv --ytdl-format=bestaudio "ytdl://ytsearch1:$*"
    }

Edit: as per comment below, swapped '--no-video' for '--ytdl-format=bestaudio'