SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efb326970deebda7be336b584d64135fc3b729575cdbdcc9568553eec6f214db' 
  AND token = 'Zkyibyy6GJoLq3xSjX5kUIwfXe3mwEGYki+Ag0RztN4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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