SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd8051601e1c5d2befb7d68a1d547f8e729692ef508dc9ab5929ba56747470a91' 
  AND token = '3fIgA8TWF+2dpEz7tz5W1TBzgF1lUif1rQ4/6wXM9cU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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