SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6aef9c0a10f5f45b65e1ced221085a67920748879cb5f31772772ed60a343821' 
  AND token = 'gLgap5uv7SeOkNZ+/Er5PH5dqb6wvISOy6m2UU5l34U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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