SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1fb9f74932183b9124ce19a66b95ee467de502feead653a43866fd02b915815e' 
  AND token = 'ZtLoP0MMSfuQvYJb5Rkyjou4Kgtu6LTaN81ZOV03Rdw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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