ERC20 tokens (e.g., CVC, EOS, GNT, WAX, STORM, SALT) do not have their own public address/private key pair shown in "Display Private Keys." This is because ERC20 tokens are held on an Ethereum address, so they share the public address/private key with Ethereum.
If you would like to see your private key for any ERC20 token, please make sure your ETH wallet is initialized from Menu > Customization > Manage Wallets > Ethereum (ETH). After that, you will be able to see the same address as your ERC20 token along with the private key for it in Menu >Tools> Display Private Keys> ☑It's safe > View Private Keys > Ethereum (ETH)
Disclaimer: Please make sure you do not share your 12-word backup phrase and private keys with anyone, including the Jaxx User Success team, who will never ask for them. If someone gains access to them, they will also be able to manage your digital assets.