SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4deaf0f85135e7d622544b28c8461d5953eeaa7670bc947ca7d8f86d2183d7d9' 
  AND token = '2zSfuKnnkxQpjbMD/th4LgUBgSwAb/5+NjHQXdTdWtw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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