SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9d9d7e9d4994249b9a41330584cc885155d0d6e55e8ee2bf30ea833d57c3606' 
  AND token = 'qMbun/kpklNL87oWGAXDz6yIBjxnkeGGJ7FzIQn2Hwg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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