SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '8fcea0deea965cc8eb9d245a4df8cfdb04a4a6114f5a3879ebb69c8bca7cc4c9' 
  AND token = '0JKFUyPghiSiByGBGHrH2WEIEkQIMMIIX2mJ+Nx8VJQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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