SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a33080e3e16ba6cc96b17075e9a7bd281bc1c8058faa2abf154fa4be6f3fc4ef' 
  AND token = 'HzLlUBQ4KXXc9mIyL2uSLubnMg/LcJrm3T/+c0j5Psw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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