SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'ffb70f9f09d09c97ae8db2b9565b2cf4c9e258ee3734a51fe6028286cbb04f9d' 
  AND token = 'nb3s8OkxC/8ZX4ehcxlNdi8EHqFDx4r4T7hubJs0BM8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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