SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86bb64b17d04e015f0b41ba36a881294a2d0c53e27522e8dd9cdf4966ba986cd' 
  AND token = '04KqhBUXe13YYxGNoe3BqIU4mz/wPu5ZcjbS2zJGzlA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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