SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '0e2a4a6abcab045630319b53d19114b268739bd7f9f405450c7782de1b0abd23' 
  AND token = 'L+V690p5/Xf+mYL+sOE4cGYZ6UBjqlmCa0Tvg2YYSyI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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