SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0bb2845684d7018727a948d59e9c3791650ac1278bb356c2ccfc628fc2121d9c' 
  AND token = '+xWTmKfCf8D/fHunNffdWl5Rqnoj3LCuvvxBb1IrnH8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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