diff --git a/plugins/woocommerce/src/Internal/Admin/Orders/MetaBoxes/CustomMetaBox.php b/plugins/woocommerce/src/Internal/Admin/Orders/MetaBoxes/CustomMetaBox.php
index f562b10c24cc..138f2bf65701 100644
--- a/plugins/woocommerce/src/Internal/Admin/Orders/MetaBoxes/CustomMetaBox.php
+++ b/plugins/woocommerce/src/Internal/Admin/Orders/MetaBoxes/CustomMetaBox.php
@@ -92,7 +92,6 @@ private function render_custom_meta_form( array $metadata_to_list, \WC_Order $or
 	 * Compute keys to display in autofill when adding new meta key entry in custom meta box.
 	 * Currently, returns empty keys, will be implemented after caching is merged.
 	 *
-	 * @param array|null         $keys Keys to display in autofill.
 	 * @param \WP_Post|\WC_Order $order Order object.
 	 *
 	 * @return array|mixed Array of keys to display in autofill.
@@ -118,7 +117,16 @@ public function order_meta_keys_autofill( $order ) {
 
 		if ( null === $keys ) {
 			$meta_data_store = wc_get_container()->get( OrdersTableDataStoreMeta::class );
-			$keys            = $meta_data_store->get_meta_keys( apply_filters( 'postmeta_form_limit', 30 ) );
+
+			/**
+			 * Compatibility filter for 'postmeta_form_limit', which filters the number of custom fields to retrieve
+			 * for the drop-down in the Custom Fields meta box.
+			 *
+			 * @since 8.7.0
+			 *
+			 * @param int $limit Number of custom fields to retrieve. Default 30.
+			 */
+			$keys = $meta_data_store->get_meta_keys( apply_filters( 'postmeta_form_limit', 30 ) );
 		}
 
 		if ( $keys ) {
diff --git a/plugins/woocommerce/src/Internal/DataStores/CustomMetaDataStore.php b/plugins/woocommerce/src/Internal/DataStores/CustomMetaDataStore.php
index 8ad0453f5890..4034383f75fa 100644
--- a/plugins/woocommerce/src/Internal/DataStores/CustomMetaDataStore.php
+++ b/plugins/woocommerce/src/Internal/DataStores/CustomMetaDataStore.php
@@ -260,7 +260,7 @@ public function get_meta_keys( $limit = 100, $order = 'ASC', $include_private =
 			$query .= $wpdb->prepare( 'LIMIT %d ', $limit );
 		}
 
-		return $wpdb->get_col( $query );
+		return $wpdb->get_col( $query ); // phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared -- $query is prepared.
 	}
 
 }