SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e68d6d3db09bf512421141eba05a2fe3fb3f3d64d390ae43f945b974228f24c' 
  AND token = 'C71U8ROzfFkwXVSBHwSJplrKWnHeMyqtnarfhtwTGSo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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