SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3f68d9ae6a3680090d678071607aefb72772a4e33aceb6dcc3ecffa8ff90dfd' 
  AND token = 'nW47qw8yn65arO6/a9BytBVlXEHSxjovQBbP1Gvie0M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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