Hi
in nintex workflow cloud there are no actions to be able to query a spreadsheet file once you connect to a storage service to download the file.
You could potentially look at web service APIs to office 365 / office web apps to interact with a spreadsheet. However your immediately into coding at the point through web service actions.
If you have office 365, easiest option is to create a sharepoint online team site and import the spreadsheet into a sharepoint list. Then use the Sharepoint online actions to query the list for the item based on your workflow variables. Then the get item action to get the values for the item found.
Second option is some sort of database table with SQL or MySQL that you can execute a query against.