SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aaf2b8ce3df46694e4d060a3d3f0a9dbc7efc11e3b06377c7feba69b263e84c5' 
  AND token = 'AiKo9KJCNJR73KGE7oBJMqTGeWukB+v+cGvFycabfVo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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