SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '271498c35126e296e7aab6ff37bf41f8a94c0037488d53a69cc0da310c7eb2ae' 
  AND token = '0VwO0k22EAmYvh/XTDxwg1d5OftqdfC+HIAqZy6kKHc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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