Not seeing error in code

I get the following error in the dev console. I am not seeing where the issue is.

{message: "syntax error, unexpected '=>' (T_DOUBLE_ARROW), expecting ')'", exception: "ParseError",…}

public function store(Request $request)
    {

        $customMessages = [
            'mimes' => 'The :attribute must be an MP3 file.'
        ];


        $this->validate($request, [
            'title' => 'required',
            'file' => 'max:20000|mp3_ogg_extension',

        ],$customMessages);

        $album = MusicAlbum::where(id => $request->get('album_id')); -- ERROR HERE
       if($album->user_id == \Auth::user()->id){
        $music = new Mp3();
        $music->title=$request['title'];
        if($request->has('file')){  
       $s3 = \Storage::disk(config('filesystems.default'));
       $path=$s3->put("/music_album_mp3s", request()->file, 'public');
        $music->mp3=$path;
        }
        
        $music->music_album_id = $request['album_id'];

        $music->save();

        return $music;
    }
    }