SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '33516768d19754d5a0b45f34578922da1c23bca199358a6d8021f77da5f578bb' 
  AND token = 'ZqHjUuk4d3eeAf0cWwcSJKdKRKFO57yLjax/PYk+jDk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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