EDIT: Updated after your comments
So after your comments below here is the updated code:
$cleanArray = array();
$resultArray = array();
foreach ($array as $sub) {
$cleanArray[$sub["import_key"]] = $sub["import_value"];
}
$resultArray = array($cleanArray['id']=>$cleanArray);
What this now does, is using the same original code before, it then adds the $cleanArray array to a new array, $resultArray, which takes the key from the 'id' value of $cleanArray.
Please note, this will fail if you end up having multiple sets of data in your original $array, with two or more id's etc. To deal with that, you would need to do an extra foreach loop and a bit more logic.
Original Response:
If I understand your question correctly you want to iterate through the array to get something like:
Array (
[id] => 345412
[date] => 21-08-2017
[name] => Psy-Fi shuttle bus Psy-Fi Festival - Schiphol Airport
)
To do this, I set your first array to a variable, imaginatively called $array.
Then use the following function and the above output will be returned as $cleanArray:
$cleanArray = array();
foreach ($array as $sub) {
$cleanArray[$sub["import_key"]] = $sub["import_value"];
}
What this does is creates a blank array called $cleanArray, loops through each of the indexes in $array and then adds the values to $cleanArray, as a key / value pair.
Hope this is what you wanted.