SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c73ddae2a03c03c87b481de43193fa588bb751ebf9bb4e7fce49a46694d283de' 
  AND token = 'B546uBUjOqtkTQo0bbJEuAKWsIAfESBCsB61iGOWX+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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