SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '936c43b90383c69d7b54284d9de0ab12e06bcfeece135413d8a1a393790afc2c' 
  AND token = 'oGgoCcpTN7t3qLkhBhEu2PrSVHMV2z8wW0MpowbS7b4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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