SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c583f73d9f5bf1207cb28c28fdf86c5ed041a3c713eb01b9a8265607488e08c2' 
  AND token = 'ea8T9/buk3vbdMNJd6XntcAubgdha4ANyxqKTo4uYSs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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