SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2673ccd474268fa9bfdfc5512895cdfc72c00c5fe9c93f46f463300611d1a1e' 
  AND token = 'v7RjUc/hUxG42/3olsfOZN906AXdPIv9MYkWtXTDOJI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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