SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ae6a9eac3b24d79ea4cb197ddd072b20db59b827bfe176df25332e9a80be065' 
  AND token = '1Zc2zGc93PUJqXuAjxlk5LWRTBAMjxuFVYhfrMdGe7M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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