SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47553d5134355db60fedee9c4cd5bf3457c7c2896e0ab4a74a214750eefb7a6d' 
  AND token = 'LzyK5wH8QzzwDEPlUGzR2azFeiVu0zreDbL/NzVGO94=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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