SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a92f4887d91c56e3edab69a2f981c32bc5d765fe56fa63760bb85c6209d42508' 
  AND token = 'PSh/vIH0wRm/n+mPWRcoUm+6k66nmY5OvwV6GVyHzp4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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