SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a94a8af4000bdac84eed4350856b8405d052ad4117a09a5f9301349e4afab481' 
  AND token = 'YypzvbwsxRpKcC7D77UVGncpxmKKnKuuT62RS6J7AZc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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