node_redis_connection

index.js

let
  redis     = require('redis'),
  /* Values are hard-coded for this example, it's usually best to bring these in via file or environment variable for production */
  client    = redis.createClient({
    port      : 6379,               // replace with your port
    host      : '120.0.0.1',        // replace with your hostanme or IP address
    password  : 'your password',    // replace with your password
    // optional, if using SSL
    // use `fs.readFile[Sync]` or another method to bring these values in
    tls       : {
      key  : stringValueOfKeyFile,  
      cert : stringValueOfCertFile,
      ca   : [ stringValueOfCaCertFile ]
    }
  });

OK. This is pretty straight forward (if I understand your intended use). You could create a class to do this but honestly, I don't know what you'd gain. Here are the things you need to know:

• node_redis will manage the connection for you - you don't need to wait for it to connect to start sending redis commands, everything will just queue up.
• Upon getting data the id, you would execute a client.get to your requested key. In Express, you can do this either in callback directly (app.post('/whatever/', (req,res) => { client.get( .... ) })) or implement this as a middleware which would be cleaner.
• 500 requests per second should be absolutely no problem (assuming they are not gigantic). A single Redis instance should be good for tens of thousand ops/sec.