SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd6f69f813a76ce97a6eb6591c69e94cedfc31abf5c90a49d8c31afa83ffbfa8' 
  AND token = 'haLiWyQj1N9v/4s5Mem69VrZWoYpcNmeIpl3OSrWIIA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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