SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d168121197ecaa38abac3d56138705d328c21179d08ad402493436e986763f5' 
  AND token = 'gBgHGJC+yLfNc8hbVV+mTdIQnDpGBHwJZdnIo5Mff60=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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