SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5311c09e3038acab73f2cc58369307f4a9029666752b5083ea428573a9b9eb42' 
  AND token = 'TO09koWOJIvYjAL5qlDSy1jT846QpOcED9a0VwpuAJo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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