SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '770d85a99e4dfd1dff50121a8bb7ffd949114282c4203893daa3270ad730fb4b' 
  AND token = '4OAHc5r2OMIEAESeVw5XvAMUUBlNnNZwjdQdKgKoynI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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