SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b7ba0a6c61a828da43fe5f787aed8fd88ca84a6508d97b3c364993048d3839f' 
  AND token = 'xvB+ih1I7Uc4kWIEZ5Lmamdr7OUMxpi850JkOlE/O1w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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