SELECT 
  1 
FROM 
  tmall_lock_keys 
WHERE 
  key_id = '28acd11c732fc65b7c1a77e97ad58df7be4dbb821eb886cfb7b32635be5bc805' 
  AND token = 'sDjgR0fxq9CcFnSGWNC+zPHgMVz4CgzKA1maUKriCsQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00924

JSON explain

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