SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6aa3ea74f768296dc399d9a883fc96caa74c67bdb40cd28ce529ff3b20fcdc6' 
  AND token = 'JUqAHcEanbuH0CXRX8XxiVCN7nywwH5KTc28dwVTxMo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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