SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ecebe3fe7b62c51a4fc77e4477aa1cd3a147d5bf4bd7ee9260cb807a2f194249' 
  AND token = 'skhCyqM9UtzxAkTjfQaq/uhUGuFQ7Seja4JglQCRzZ8=' 
  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"
    }
  }
}