SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3d51ed025cb831aac0333d954c89613ffa7258878c914aa727f8fa813d4af532' 
  AND token = 'Ufk1c9dd7hJU1UIlS14rm6VL+0tg7lv4YzzRcwXHusY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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