SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5731c83d0e44cece03dd9335d04d35da099d9a2acdbd1b5e52ea553e3bc419be' 
  AND token = 'jtBqp9CdvHPW5XdIs8lwESGvyBwUV1bHUu3PnvZHjuM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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