SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70c899b4cc6d70606c7851446064c9859267c6899c208f0eb1e0dc91e3acfc7b' 
  AND token = '1EoEWh5XQJLTAdk7NO5/a9IP/JdVRyJRC8mvD7Jj9JU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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