SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '961986ba33d19f11aa694b5a7f4bfa192c114dad098793ab83c3594edeef862f' 
  AND token = 'PSylbgV3y0QrOg1qqY/NUFa5jUE6XnfUUFaghB7M4Zc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}