SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '748bca337a8b87b1f3ceeac063db3b0877f8a0d85dea9822d665814ff0f24e43' 
  AND token = 'L53VdETWdryqjk54V/3X+thtljOeqIpPGxlxs6QrLQA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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