SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36b617eafb5374afacb6db1e68c2787898db0bfb66188cdfc5f62c7592679140' 
  AND token = 'ZH7qZibg0zrWjtVX/1OzpzFDMWPjcSUDUExokGv50+E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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