SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad13ecf6f12229551e013424c8242eb3662237340164dc5eb2d8bb3003fdc1f1' 
  AND token = 'yU6kUYiEuogjNLIHs5VpnRufoKwUQgQwFJB61opGxF8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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