SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da8ea117df159d7bf61bc8ab40cbdb67821d186a058a822948f8ac9bcec6d92a' 
  AND token = 'uKgQ5mh/ZQiZIE22T/5HbPsP22pho3y/rFlnwbd6jCM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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