SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4bd728cec21cfb3c2ccc537cff6092fb9dc9caad5593552baff6c44d938e26f1' 
  AND token = 'A/l6yoVciAW0lwgnM+TmC023EZKTrnYjLmKltOFjzTw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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