facetwp exact matches for autocomplete

<?php
/** return exact matches for keyword searched in auto complete **/

add_filter( 'facetwp_wpdb_sql', function( $sql, $facet ) {
	if ( 'keywords' == $facet['name'] ) {
		global $wpdb;

		$facet = $params['facet'];
		$selected_values = $facet['selected_values'];
		$selected_values = is_array( $selected_values ) ? $selected_values[0] : $selected_values;
		$selected_values = stripslashes( $selected_values );

		if ( empty( $selected_values ) ) {
			return $sql;
		}

		$sql = "
        SELECT DISTINCT post_id FROM {$wpdb->prefix}facetwp_index
        WHERE facet_name = %s AND facet_display_value LIKE %s";

		$sql = $wpdb->prepare( $sql, $facet['name'], $selected_values );
	}
	return $sql;
}, 10, 2 );