SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '59de8280f678d24c7c8c7594f300dcab1516f62cedbfe08822484abc52edf916' 
  AND token = 'lj1b37pon5M8vMbnvVRFWe1TZlWqm09EhwK2fH1SHTY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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