SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cdb9ec57a86486886156e1029225023bbdbbfba38e5bbcd12ebe5893d1dff6e9' 
  AND token = 'ywg8mwfbxtz6wqhgqXSglaUF1ixIv7gEZf2mmX7dk/E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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