SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1fd7c1dd9761256888272816594eb8e5e2cc3bbb1198b2b8b82586e16887b5cd' 
  AND token = 'VUNYF/xqWih4uuVLztKKuQIDckAd5j3PBJ0y7PAnMbE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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