SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08a1a7c22932eee4939ccb26b3c988a5313ac508c44f8e1fe04e8c464b34cfa5' 
  AND token = 'nFCjTkzUNk4IUJvrWp4UEVMlqDxyyF8tVDkrpsRFcnY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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