Super Simple API IMEI Checker

I have a Wordpress Site with WooCommerce integrated.

Let me point out! This job does not require skill in either Wordpress or Woocommerce!
I changed my terms from last time as people were charging me the price of a car and jewellery..

I work with an API Checker Site which works the following way:

1) You append the IMEI number (which is what people input into a text box) to the following URL
http://sickw.com/api.php?key={API-KEY}&imei={IMEI}

2) When this URL is run, it runs the check in a few seconds and returns plain text as a result, like so:
IMEI: 352829061xxxxxx
FMI Status: Clean

* All I need is simply a text box (which has a validator accepting only 15-digit numbers, which is an IMEI)
* When the user clicks the button "Check Now", the IMEI should be checked using the URL structure above
* Any form of loading/waiting dialog/GIF would be appreciated while the check runs
* When the result is received, display that text exactly to the user

* I want this script running solely on one of the pages on my Wordpress site (so that I can still hide the page or password protect it with WordPress functions)

* I obviously don't want the API key to be accessible by anyone so they can abuse my API account. My website is SSL encrypted, if that helps with hiding this from unwanted eyes!

It's a very very simple API call, maybe not even classified API. Please don't rip me off for something I could learn on my own in free time.. :)
[API Samples attached]

Thank you for your interest :)