SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9261b5294d779d8222a46f140e0c34eaf13c088a8f7c9b26e5cb6de2d802f52e' 
  AND token = 'QKjdCvaIFJtRvTyZoUH1WAzgHFMxfAIheWAsgv3Rhuo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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