SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7629cc69a84a0bc8fcd4aa26dde5f1ea14742fb74973581f62c9f9f74d243ad5' 
  AND token = 'xwJjwqhau9gfzx++ZDj0guE9mfj8Q1dxx9vtk8BDgOA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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