SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '66d60600bb12135eb4f912b65fd5304c25614a9763d66984618450ed35c8b761' 
  AND token = 'ErpdlWJm0sLaqPewojyo6HseG2qi9AyeoCZb5uxi4wY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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