SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d3daaeb22c61fc5b94f8a532cf373505ca692816f318c41bdaa8b17b4e59559' 
  AND token = 'ilDjTaqDGfgC/17AwdwKPR7sT/DaBunv1MVrF3KiQ7s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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