SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a4157816a29da4a08aef76510c49ded20cc5ae970a7f880073b759a0de0e943' 
  AND token = 'vezWCcbZzyyWt59cjrY+o7JniwVM+32QIY8AjhJlgeg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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