SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe7a5cbd3879c44ca8494a038948c2a83053d90f27e211df5788ebd6a2432155' 
  AND token = 'J8gMlAerxt0156bqKuVacxQQSvHEzuLjy5lnje7DD24=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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