SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '326885c8d71d20c7b8a033b75e76198941f0875a263e84bf74a7b24239fe483f' 
  AND token = 'x3pnnGYQdS+h71GfI1mo+KjaCJG0ttwkKV7snBiQU0U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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