Style your scroll bar Visibility, Color and Thickness like this:
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/recycler_bg"
<!--Show Scroll Bar-->
android:fadeScrollbars="false"
android:scrollbarAlwaysDrawVerticalTrack="true"
android:scrollbarFadeDuration="50000"
<!--Scroll Bar thickness-->
android:scrollbarSize="4dp"
<!--Scroll Bar Color-->
android:scrollbarThumbVertical="@color/colorSecondaryText"/>
Hope it help save some time.