SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1edf7751a4f3c14f6aa7ed47ab93a85d1ec3e231bdc34dc91bcbaea2f8bfde12' 
  AND token = '2RvnW0zqKhXUkMB9AZ0GwsIsg0zsUYRfAlSZGOhzi/4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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