SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '9cf4ba43cd00166f5fc7ad3f02ae17035724c68a206273d2482f8e9aff1f6751' 
  AND token = 'xWvr0TjiXBXjAqNDcjiI5LuJPioQZmuKoJtiSl82ih8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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