SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fdf81236c5332b11624db0177b1de13a6a47a4421d854e2254ab59cab0bd6f0f' 
  AND token = 'GEtJTiq3u8FZx5XoPZc4qijZhopnhVvPYauWVJsI9qE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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