Sandbox

SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4b6edc8d19caafa79aeb041e11e87be954fb2c03350e78fb4dc7d01b705fde3' 
  AND token = 'PWhnSTJYW05Zvg5qQIUxxRqBSLz+hGGFyHeeUFhEZaU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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