SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '891723fd3b253ea7002345d9586765f00cb294c4f22f7fbdb3626c577e434cc8' 
  AND token = 'LZEGyhenUYOMfjKkbiPWVjc6OvDw422oagJi73qwY1Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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