SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc77bf0931d541dbe44e7e9e2da31d63f011d85422a363b4ca506bfae4ea161c' 
  AND token = 'wWDcGZtVFnrXGqJh9ZOxHxS/Uun+4Pv5yS6Hw1/wHQA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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