SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '843d7b9b42d708d7b60d5e59e41585634d1d911f148acbb96bd0385978844560' 
  AND token = 'jHx82OPQ1HhCMx1k2nzU0nQ12ghmmgqyzwhh2dRIvq0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00083

JSON explain

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