src/Settings.php
private function update($key, $value)
    {
        Yii::$app->db
            ->createCommand()
            ->update($this->tableName, ['value' => $value], '`key` = :key', [':key' => $key])->execute();
    }
private function update($key, $value)
    {
        Yii::$app->db
            ->createCommand()
            ->update($this->tableName, ['value' => $value], '`key` = :key', [':key' => $key])->execute();
    }
Update setting

@param string $key
@param string $value