SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '849ad79072029943dd464fb093933735cc59a7816202e39c107b6bc5838a47f0' 
  AND token = 'QOEQvnaiXxP4Mkm6YFLIINqOGd/ZPjdGCEwKGbRT4Aw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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