SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3fcc42ec44d5e540daf3522c819a20da5c009fd498933b42dc64d862bb3795c' 
  AND token = 'UoaAIPERThZFqQyn5HMOT6cVSXXx/q0b/Zjnu4t9cP0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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