SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d96e5adae4afeb4281398c408090de34824395e6434b476d95da39fb127bb1c' 
  AND token = 'DbFl6QwNakocGJk2KLM3Br6n6CPKUZlvUcrfmSNsuW8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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