SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89ba0e2a206d39b4caac821c663f1324d5b23416ed21ca734e630f0ad2a22e34' 
  AND token = 'AJ6aerLvJKRPkDZT8FviGMHjz1ThQhHj7PbXhbVHL/8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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