SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '0c6242035d1704e279ee1a982ad7f86bc9f0c453def2fc43d925341dd9e5f91f' 
  AND token = '8XqF3IPdgaY5ujH6wMvZDu5y6CY9pGx+zy8Wu3iwS9s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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