SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '463e8fd970d73ccb43e7f4431cb5dece38ee3452470fb24407ef22d7fda809a6' 
  AND token = 'W0aCZiK1l6HD2lxPvYmY+GvQRwLMjk8p5NpaAFL/5xg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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