SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '495ab318059dbe4d5e4a60f6ec671e3dc2e9cc2fd256481560576675ae6865f4' 
  AND token = 'RNTJCZEbTzYEK27O0cPUEDZLRxvOGf5oGNSQ19RyJuA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00009

JSON explain

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