SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5cc19e15600c36728d0f1675f4ac874cb49fc5c36cf8546cc97c21a5f7d940cb' 
  AND token = '+umODg/D5hJCaUjARYEIl5Mf3JR8BgHr+siImHN+/1Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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