SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '2463c1ff4b6d4edbb00faa859be7281c8183529d737b85bb7ed224418cb75f01' 
  AND token = 'U9PYHUyUXF1lUVt+Vp+fvDtj0yFWaQf+QcmNtOAc/q4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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