SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b7fda4e4e24b0e44b369d1887a12d0576f1fd288acc44f8dfa3c83612332a06b' 
  AND token = 'TjWl56A9Ia7YlURXwXnjtI29niQvvyTW1eG5ghFXTzs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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