$re = '/(ART\D\d{4}(.*?)\DAND)/';
$str = 'ART|3613{"currentTime":"2016-02-29 20:57:06","chat":{"user":"SERVER","msg":"asd"}}|AND ART|8923{"currentTime":"2016-02-29 20:57:06","chat":{"user":"SERVER","msg":"asd"}}|AND';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php