SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0cb044ae0dcac5d36c151906c0b268aec8baeaa93d10fe21b005938841451eaf' 
  AND token = '1+vvVk0MUNgmeuPKXoKKsszmMzIBJBH/5ME3QN/6NII=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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