SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9866ac4c38e04b03266ec2d1aae7798899085468f5d71ca274f8bcd8e851a4c1' 
  AND token = 'hwn6h6mc1O2vGaHd+q8ouwT6Sr9TJy4BGOTr+eWRtpU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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