SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78162f98214186b3c0fcb8f4b73f97aa038f82f7b88ec655b32329017fd79b29' 
  AND token = 'Yj9Y8lsjnA+drk7Clrl4Nj1qTTGcB/1wgeIlXBwGRVc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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