class Order extends Model
{
    public function sms()
    {
        return $this->belongsToMany('App\Sms')->using('App\OrderSms')->withTimestamps();
    }
}

class Sms extends Model
{
    public $timestamps = false;

    protected $fillable = ['subject', 'template'];
}

class OrderSms extends Pivot
{
    protected $table = 'order_sms';
}

OrderSms::where('red_sms_id', $smsId)->update([
    'status' => $status
]);

As result is Call to a member function getUpdatedAtColumn() on null. I have to use:

DB::table('order_sms')->where('red_sms_id', $smsId)->update([
    'status' => $status,
    'updated_at' => Carbon::now()
]);