With GraphQL for Unity you can execute GraphQL Queries in a Unity way with GameObjects. But with the asset you can also execute queries in Unity with C# code.

Here is a simple example:

public GraphQL Connection;

public void ScriptQuery()
    {
        var query = "query($Token: String!) { doit($Token) { result } } ";
        var args = new JObject
        {
            { "Token", "123" }
        };
        Connection.ExecuteQuery(query, args, (result) =>
        {
            Debug.Log(result.Result.ToString());
        });
    }

Link the Connection variable to your GraphQL GameObject where the connection is set.

Note: the result callback function is called asynchronous and it is not executed in the Game-loop.