SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '815b14adebf6200b39ecdfc4477d8caae441f950d80101a48379f5f405d006d0' 
  AND token = 'uG8EtB4CbikGjVr54PXfbzIc0+5/hQRPPus7FkInXOs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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