SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '673fa7b9cf82b722a7eff196bb00338d0688fee800dd634a94b7a241c99463fc' 
  AND token = 'hAMn20JUvsrfgabW7tEn+5zo6qqlIx8VubgZxnh1eQE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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