SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '359bb4921934f14d932d346d2800065a9a60c1f181eef3edf2cd6a3759ce20ea' 
  AND token = 'EWcD7HKxPoWDajnr7USIuDo7OTipAS51ilP8uYppYTs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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