SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff35a98bf958c50ca4cd4898ad5720c27bd08c21d0c74ea4c8b565f4e33e17d3' 
  AND token = 'QwbEichj82vLAq5DjM0ngL9F7JTjpBdBkBOwWR/w6OY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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