SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff0979226afba3156eae3c4554ff8f27eefee44a902b73934e1566915e746cdd' 
  AND token = 'Tv340dL3JZJZyJD6jmihnOdwPnA3GGZhIyKK24A1MBs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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