SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c402c830f21e8d687adbe8d1eaa58fca98c26165103db8f80d483e491189c52' 
  AND token = 'Hqym0MbcJnRzA1EEQywLrMfDqwVNtMs2sYFcZyXmYCI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}