SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f59a613ea34fe976fdcc66109192168cbb86e647dc078d802a48df847d02c4e' 
  AND token = 'Mc4C47spExKjRypMcAlipkRRSZnLxS5c9oilzNuAAi0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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