SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0642c9ab5808d30c85313161b5a3dcde8cb2d03267d5854ff6bfd033c760157' 
  AND token = 'aRC6SKJOgSIP/4uTx8cwBxOa6vUYm7OmEl0qd27Zj/E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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