SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6820a854c3839da700157b4f791615adb161e763ae8391c66a1669b7cc9ee09d' 
  AND token = 'AkoRVx0lFvuisgSBnPu5+b7LPhPE0TgGBVzEe4dNpts=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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