SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0aa21d5ff75e7056a30dd8ba1c399641d874a598a81d3c7573cb56ffa3bb3bcd' 
  AND token = 'K+Azw1lec7k8Euz7JeNqBmwDXi+GT8K0P0s3h0/HkvU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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