SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85bb38a682fcd81fcd807fb8f4d09fcd6bc6476f4854ff90c858f622f2347e6c' 
  AND token = 'egM8ifnhF7j4EZ8lbI5M8623CFqNHEgJ3lJZX9ZVcTU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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