SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e4d6ec8067c5b9fd13afe8083fb0c438f0b37948390a8fddca931fb4f202e38' 
  AND token = 'W7MfjFcOqGgemEna6FCEGYXpK9PvJj2n+cz8wuBkNGw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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