Android SeachView: How shift to the right microphone's icon?

Question

In my fragment I have searchView. And it's work fine.

Here layout xml:

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <android.support.v7.widget.SearchView
        android:id="@+id/searchView"
        android:layout_width="0dp"
        android:layout_height="30dp"
        android:layout_marginEnd="20dp"
        android:layout_marginLeft="20dp"
        android:layout_marginRight="20dp"
        android:layout_marginStart="20dp"
        android:background="@drawable/search_view_bg"
        android:theme="@style/SearchViewTheme"
        app:defaultQueryHint="@string/settings"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:searchHintIcon="@null" />

</android.support.constraint.ConstraintLayout>

Here screenshot:

But I need to shift microphone's icon to the right (on 8dp). How can I do this?