SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '208031c51015f246d2e81ead5ddb346bf3f3816768dca3bf36864b8cda2c5dfc' 
  AND token = 'O7CfESdpPBRxIYI05Etyj/J0dPswfwC6O/HPXDk+kRk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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