SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43a5fbddd062207489465ab2c637bdc9425ff1eee66fbab2603b55eaee969d91' 
  AND token = 'tr12nr8TYvVIUOQ5cvClW2bwNYyKjmWG91VyKNUH4Us=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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