SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70c788664fa066b066821c6f7b6f92d6d6eb37a74dbf30ce3ede498a052eef20' 
  AND token = 'lhYsZTyFtBfJqBhgZRaCvwDzfCt++g2PIJvaq8hFqFA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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