SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6ccc70281ad6aaedbd2ac4985423822c7d563b0a70849d1be79fe3d3392d6c1' 
  AND token = 'IHYcf6yQnzglQn7gkuCM020K5PVq2K0y0kVdWr2yCZM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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