You can see the following code to solved the problem
return $query->join('kg_shops', function($join)
{
$join->on('kg_shops.id', '=', 'kg_feeds.shop_id');
$join->where('kg_shops.active','=', 1);
});
Or another way to solved it
return $query->join('kg_shops', function($join)
{
$join->on('kg_shops.id', '=', 'kg_feeds.shop_id');
$join->on('kg_shops.active','=', DB::raw('1'));
});