SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff97ee08d46ca19126cf9cbae1ddf0af795ec048bff1ba2ef397ece250e931af' 
  AND token = 'auAllvqh3B0gnOqw1ZiCDA31hj5b1NBwLYrA5FJdmyI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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