SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08076f1530a6bf2f9c32bdc2b222f1cc47e6a4012154b6ab28b40e7cb128112f' 
  AND token = 'mNgZ9AixrUmixTbpES7XJRj3KCwYTxYZU5moWhEK2G4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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