SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8a6fca75de2137d0dfb7559c130516bf198398bc6cd55e9d0dffc7b2dfd3a8e' 
  AND token = 'CLKPLC0rqp6qbBYLz54bQdHbFGUxERPuB1yVh9pgPDQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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