SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9afe2f0bc1cd01fba31be33ac7026677a0e0bb82b2698d2b0414cc739b60a3f' 
  AND token = '76qhIXm3vdY9nHaxlRD5CW9Wk/6mRz5pWQt7finXl0g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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