SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '817b9fe397f712ffee522e5e7c05bd2d899ae5d5629e05968123934c31551c28' 
  AND token = 'xDfQt6bbSSCyDtwTDkvhfCfn4SAuNEibj4Di5gE2kU4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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