SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e96b849658f17d69aaf99d31354803fb0db1880ee79af4fa9ce238d6898de6da' 
  AND token = 'SmXpxlMSseBYU1LPoc4JhGQlE+58UvVDj0I5p3m2py4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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