SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9081b07babf3449bc3f4ea461b3637214284c846e68f06a41237daea9013d08c' 
  AND token = 'R6qGn2IQumtXjpkeNqpyKvYZsvuUAYSDAkliitMRWPw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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