SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70d9b17077c690ba1b79a37bb50c228aa7fa4251e558e20bb4a6f4bd22937637' 
  AND token = 'qc37o7b0VMzz3AiZQSnDBKr/YNAjV+H4bxp6/JBgkJI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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