SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90fdcc726547281a448929832bc04f3f13adfa7640000eeb11a292b6915c83d4' 
  AND token = 'mOBgJr+VIhOFGFU7cQl7zkguDQGqz06JlNKRmhDSxXI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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