SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '142383ca0302e3c837230f7de23693a72b9fd5e9ec080a94f9e0f63885200939' 
  AND token = '+WvFJzLvTAje15v1tOgbmJdbLBrQjruGOHIAHcewbOw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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