SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '781abc99bb9a7573d474dbdf534f12a98eec1c08fc25b4857ada4251c6ea9d86' 
  AND token = 'Cngr1IfS5xQHWSDAE0JpbBkYlz18+Zv5iAGhXj8Th7g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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