SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ab6c4a5883d2fc3e88bb9f2d55fc5f108a966b8d6d92294680952c7ee2b328d7' 
  AND token = 'd/pD0P+hwSKsWSmqIIVZZVHbcWIhITdXKG9i+QZnBKI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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