SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4ffec8e85164dafe1d0800ed0cbf8b5739b555e9f9dce2609a674d2e7f73a12' 
  AND token = 'mMvVSKohrMDkWRFnfEFn28blTrMlhQWvUNtmPjFdc4U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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