SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7fd7353822c8cd7454ed14b96127ce1cd346366fc2133fa60a351b4f014701d' 
  AND token = '0BXjSrMOHI2XOGnzbkIhtyyrVMBgOj/1Rg+NYhzv1nI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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