SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f885d6afcac11728652aae06406908aae372fc1546970003714c33cd928457f' 
  AND token = 'chx1C0s2+6YpqYBnYd0WSNArWQUU1HiGjxl+7K2UR3k=' 
  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"
    }
  }
}