SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d08bb9850708d915f15bc37e7c637527cad29acfaa49f7ece9a7e8109d50457' 
  AND token = 'wtkZHlWGTJe6ViZnNSk0aPNdWciwEM+LiTT05vVtjbk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}