SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0263a7fb5a8b9d707a7050bce82f3f2356d25467e032b703cc74bd1a509d0b36' 
  AND token = 'oh9hCUvo+XYjVl7fVGXJ4HrcKF+yNQ8nYnOyU7IsIOg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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