SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a598c51aab945e88321cc9ab962475d2fb237ddd97943db9a312afdb68b6aacd' 
  AND token = 'KgQoDwp3CM5MaGJyQXN2G8XI1P1cwt2uwyflvWqS5Ps=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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