TABLE: 'config'

id   c_key                  c_value
1    facebook               a:1:{i:0;s:8:"Newsfeed";}
2    mg_notification_msv    to.aaaa.org

public function db_get_config($key, $default = null)
{
    if (!empty($key)) {
        // $record = $this->db_get_record($this->tables['config'], array('c_key' => $key));
        $record = $this->db->from($this->tables['config'])->where(array('c_key' => $key))->limit(1)->get()->row_array();
        if (!empty($record)) {
            $value = unserialize($record['c_value']); // Message: unserialize(): Error at offset 0 of 15 bytes
            if ($value === false) {
                $value = $record['c_value'];
            }
            return $value;
        }
    }

    return $default;
}