SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6af3f181c12b4c1d962cd31e80670935244d0a99a566120642d7d7db63edf61f' 
  AND token = 'V4TuzuKN1rEDlxoingScua6Yd52sC7faOUsj91+A+XA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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