SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38ba06810933e2c0949a1187cf8a2ceaddc997882e2e98a9c8cdf46f9f812cf8' 
  AND token = 'pAbNhROGUmURtFoiE9yqcG8xYwhMbzhd2Kvg8eLssWI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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