SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96cff2c1a4533baf74a6db0940b6093c23fb8d81b3422cf5af34591cd54caffd' 
  AND token = 'YdUlcZA7Z5KaxOfgmJXCvM/JFCHAJXlCHvgoHwRkDGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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