SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9539b7d89726f83f1e73fc9e9fcdcd3df44742f51eb864633aea4b3d5e4d25bc' 
  AND token = 'RXVcCIC0/9C3KhFeJl1CZMrGFDyiQ/3ygXhuhIQsj48=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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