After a while I achieved these styles:
in the activity layout, use this code for the editText and for an ImageButton:
<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:inputType="textAutoCorrect"
android:hint="@string/hintext_buscar"
android:ems="10"
android:id="@+id/editTextBuscar"
android:textAlignment="center"
android:paddingLeft="5dp"
android:paddingRight="5dp"
android:layout_centerVertical="true"
android:layout_alignParentStart="true"
android:background="@drawable/edittext_border"
android:elevation="2.5dp"
android:layout_toStartOf="@+id/btnBuscar" />
<ImageButton
android:theme="@style/AppTheme.Button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:srcCompat="@drawable/searchicon"
android:id="@+id/btnBuscar"
android:paddingTop="18.5dp"
android:paddingBottom="18.5dp"
android:contentDescription="buscarbtn"
android:layout_centerVertical="true"
android:layout_alignParentEnd="true" />
And create an xml in drawable with the following code:
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
<!-- Background Color -->
<solid android:color="#ffffff" />
<!-- Border Color -->
<stroke android:width="1dp" android:color="#ffffff" />
<!-- Round Corners -->
<corners android:radius="1dp" />
<padding android:top="12dp" android:bottom="12dp"></padding>
</shape>