SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '2f45820a5a2f5a359ac0cdac36afb2c854b63e69e00a7aa8c876db5af3b5483d' 
  AND token = 'krgS6HqKvhlc3j0z7H/RPjpHDIxg+UMF77Z+V4YSGtM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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