SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '728ad45ec8dc621fe5b38d33975fd27771b04658dee2bd050acb3ec964dbc452' 
  AND token = 'GkRSfH1n+3BQe2NKZpl7sVQXvterOFH4O5BwuyaYC9s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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