SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '590cfbf511e663e7c07f4a91aa5833e672611a83b75a9fa72fa0cd4ccda72332' 
  AND token = 'z1AF/VxyFdDIWnCHJyx4MWpbCZ3YiK9ZqqACcIzVnwo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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