SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a4a32cfb77052a3456dd73aeddd3771913eceeba86c3bbe0d0f8b3ab80048d0' 
  AND token = 'QfMfREfU7jgRcYQVUJkz9HSPjc5DkZzMUFpviKOmJlY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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