SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8863ab07de7153094220947d77a3a3629f0ed248a7582c32a219b8baf4257f5b' 
  AND token = '3WjyW1zBQ2UZiYtPLk3eMBg+WHh1MZIUkWJrrSGUdTw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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