SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5fff5d76462cd628265cc95d3a488df94b9030701bcb9f08ca76c3cdd74056d8' 
  AND token = 'WuoGGEw181STifkKQaXmHghYadO3hoMod+xDzJ5n3Gc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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