SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '795cc17b56b1032880cfbe79fdae4afa851af4a99bac3d0619334a2c6cc9412c' 
  AND token = 'rEzCBOikGeF/iFJKvLaBjvaXdg3Z2oW7ja3bzrhZRk4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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