SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b29af74ef0568c0c26ee68af3022441e3b77ef2c4fa9bde2da91d7ae38b1c587' 
  AND token = 'DGiEXt+ECZEFGWwjJuxY3U8K2Dx6RbRY/5gJHNjHq+Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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