SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71a20781797c8996330fc0c41c51eb23a5638675b1bdfcbf710b20fff53cc0b4' 
  AND token = '3FhYzR7Y5mhJMyZx1jovvqF1/RVdLJ4qqak3HPN2G6I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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