SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84fe8792bc01fe378c076c766d160a4083656f71c666bce98cb0a9fb78875dd1' 
  AND token = '+bhDYckSuOb5yq6qYEAaVd6edUWLQFgKlY4OR6Nc49w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}