SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a7e6c40e101bf2813260dc4a2b95e0d1c1f5dc7aaf649902871938dc3d8efa2' 
  AND token = 'FIbuCOTKRmgUetjR9SfxW7VnBnLMvUfzhCH25Br8Ye0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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