PHP cURL GET request and request s body

Question

I want to use cURL for a GET request like this:

function connect($id_user){
    $ch = curl_init();
    $headers = array(
    'Accept: application/json',
    'Content-Type: application/json',

    );
    curl_setopt($ch, CURLOPT_URL, $this->service_url.'user/'.$id_user);
    curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
    curl_setopt($ch, CURLOPT_HEADER, 0);
    $body = '{}';

    curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "GET"); 
    curl_setopt($ch, CURLOPT_POSTFIELDS,$body);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

    // Timeout in seconds
    curl_setopt($ch, CURLOPT_TIMEOUT, 30);

    $authToken = curl_exec($ch);

    return $authToken;
}

Do you know if it is correct to use curl setopt($ch, CURLOPT POSTFIELDS,$body); with a GET request? As you can see, I want to give $body as the request's body. However, I'm not sure if this is correct or not, and I'm actually unable to debug this.