SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '25f11a3e1a949a5e4ded24dd3eb73c96b0a295d9f1eb9cf7f8f2b7db2a86a548' 
  AND token = 'ETtXdGpT1bHHXlNNwnjFvYOZk+AMGXopYFSK+jCIhiM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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