SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'c36f381f452306598da278798a8c66720eb8a6dc44b04369bf08722c8cce2fc1' 
  AND token = '0KCBEgOzfA3zoqRgIVIzf6yhTf2H5E+mQyfNHTCSgYc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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