SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3389bd6aef1e9475e310968b81b088c4d57be1362380f57d2428146dac9c2ede' 
  AND token = 'L0iOM8pN6pEQTa2mCRHZznuuJKvlniXpau6fiz8GU3U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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