SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fde50992f17fb9a44bc3d59003b2178f7ff107b43d328e074356c63f9f34a9d6' 
  AND token = 'rPPiBnyrcHaJrZ4mhCAwiyZl0km4tnQA82tjuNBn1zA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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