SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd540313830974b8a6e274ad7906fb1f0af9735c8f532a5856bb6b2931a61fc4' 
  AND token = 'B56Em3ENzMgSJS/LXqKdEW9ZFffpJz3SQgUnLVf1KBA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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