SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae50475322a28c3e2904ab7404c864c8908f0c878776ae93fbfb8229c814c801' 
  AND token = 'o9UHZXlh13VO2Y0MIxRwaWzYZ+P7BOk03/M8rGmYzhI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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