Because Shopify is not the facilitator of this claim we can’t speak to individual order eligibility. But the information we have been provided is that all merchants in the United States, who accepted Visa and/or Mastercard transactions between Jan 1, 2004 and Jan 25, 2019, should be eligible to file a claim. I am not sure if the gateway used to accept that payment affects the eligibility of this claim. Contacting the email address or phone number provided will be your best course of action.
If you are looking for transaction history and transaction fees for Shopify Payments transactions you can find that in your admin under Finances > Payouts. You can export your payout data as well.