SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46dd7af69c9bb5c00bcf18b772815598b9fc965380995c304258f07c97db1287' 
  AND token = 'CY/gp+tlQD1JU1qkwRbYRFJ38WxYpZBfROjatSWWPHo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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