SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36ec87a7750a972eb3e7158767125d2f48ef58ca8ebb4d4d2ae7172a83f7be92' 
  AND token = 'sObrk02XKdf6eTfylD1nvh4KT80wg9sXI6+C3fntn4w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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