PHP Curl disable cache - php

Question

I have a php script that periodically perform an http request to a remote api server.
I use curl to perform this task. My code is like the following exemple:
$url='http://apiserver.com/services/someservice.php?apikey='.$my_key;
$ch=curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_HTTPHEADER, array(
'Accept-Encoding: gzip, deflate',
'Accept: */*',
'Connection: keep-alive',
'User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:48.0) Gecko/20100101 Firefox/48.0'
));
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 30);
$data=curl_exec($ch);
curl_close($ch);
$json_data = json_decode($data,TRUE);
Recently I verified that it no longer fetch new data, it is using instead a cached version. I tried to add the following curl flags to the code:
curl_setopt($ch, CURLOPT_FRESH_CONNECT, 1);
curl_setopt($ch, CURLOPT_FORBID_REUSE, 1);
This did not solve the problem. I still receive the same cached response.
If I add an extra parameter to the api url like "&time=".time(), that fix the problem, but I dont want to add extra parameters to the url.
What can I do to solve the problem?