How could I create a class that would serve both the sandbox API and the production API?

Question

I am integrating the CIELO API into my system, they have two types of API, the sandbox and production. Each with his own merchantKey , merchantID , apiUrl and apiUrlQuery I have 4 constants for each environment. My initial idea was to implement the following:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

namespace SiteTeste.APIS.CIELO
{
    public class CieloAPI
    {
        string merchantKey, merchantID, apiUrl, apiUrlQuery;
        public CieloAPI(string merchantKey, string merchantID, string apiUrl, string apiUrlQuery)
        {
            this.merchantKey = merchantKey;
            this.merchantID = merchantID;
            this.apiUrl = apiUrl;
            this.apiUrlQuery = apiUrl;
        }
     }
}

But whenever I was to instantiate a new class CieloAPI I’d have to go through the keys, outside that I wouldn’t know what the sandbox and production key would be.

I don’t want everything chewed, but I need a north of which resource to use, abstract class? interface? and etc..