SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a046c4feb48ba9d2720ef8162eb2740ef09660061097dbab85b0cb2f4c31e59' 
  AND token = 'oKBFy6eitDKtIbKqTS58ZbAdMPfejX86Ss5Y5Mqmn2o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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