SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa2b3dc085d273d5ebc69e58af96538dc5040650b672e6821cda9e51fdbb8cc0' 
  AND token = 'VOtJQsd7l6TobCFYThdEo8hnj+IsBksLr7PEcASnvEU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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