SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '01a5c8a83b7bb65284361984e16a1cec1fe95554fb5448afcb08c534ae914b98' 
  AND token = '1W0I2VXAwNFVe4Xwl3VCyxDh1GLGCvM1uBynhTTzZME=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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