SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'aab136ce5cb3cce8231ca9ccc333c983e17d5c72a95a8a8967fba15c21ae8cae' 
  AND token = 'ARjMGmwJZWOWxw83ThCdD5PnDnKG4gntino17BU3xBg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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