SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84f73e2e834c198b07b423f7b28e8fcd5bfb5635430d318e068a3a9a950def7c' 
  AND token = 'LNNkzZ0ycXBg3pWPx/fyskh+BBOpivr6PyJTwymA/hA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00087

JSON explain

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