SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '125bf4d37ea16869640904bf30d0e7e4638ea924dfd3857cc8f99ea9d3f0e592' 
  AND token = 'ZPnfyo2GlqCfGR6bMKukCGneQLxqP7LvsOrvjL9OwTg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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