SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e81b3e9c44aa85d92341574d6888a54cbbe591fe9e2e1330b62ddc10aa64b4e' 
  AND token = 'yLIwPLqKagZ2MjI7xtgjg6/cC6bD9GMFKeWy+N8/y2w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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