SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a96eae9f4054bf8fbfff633ba21c82bbd20d5d84d3132571d20790a48fc33a72' 
  AND token = '8UJA/vbrlAhEf9mq8444VkkI5/bg2pZcZKAVOW+wjc8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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