SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '200901378b17ff892126132d59dfbd0792cc24d01e573e6cda293a564489b278' 
  AND token = '+OzMY008YRqYOzsnNN2Z9kwVzDHOktKC1aAfjw/KLzk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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