SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '9bb62bcb48d9c24f062808e3695fc1635b4e1278a24f182d435126baec9a7650' 
  AND token = 'yhdH5gr3Iyhi9qvQhlRzbe3kK3MTUFesSZ9pvcs8wO8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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