If I want to look at the generated query, I have to do this:
$queryParser = \TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance('TYPO3\\CMS\\Extbase\\Persistence\\Generic\\Storage\\Typo3DbQueryParser');
\TYPO3\CMS\Extbase\Utility\DebuggerUtility::var_dump($queryParser->parseQuery($query));
That doesn’t show the query itself, but at least all parts and the information in tables, fields and where are quite helpful.
Edit: Nachtrag: In typo3 8 this changed once again.