SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83941daf937ccfe5cc070ae4cf2249924c922d92fffda88b3e4d8350e7002981' 
  AND token = '4yFgh0fOyQ1BvvFBxz8/wKEXKoTOS7jfF/m6QJY9DUw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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