SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '4a7bb4b7daff961ccc2a1d49014edf2066f28d5e25511fb8a2bd90d572ee7b1c' 
  AND token = '91JJCjX+zUsCphcnS6fkXndBTImFyRUEHgmFZ9SsVL4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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