SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ec01db5f4e704b941ead4ab274df83a69429944524bc134e124eee384bde655' 
  AND token = '6wWpQklYfryWDFTH//2Thzh2UxSTfA8BuBy9Og82tTw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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