SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cab888f6550f10b5e2dcb642865ff7acfba97714543e0be63d351a0b9c851ee' 
  AND token = 'VYQxgi4Hxh2KghWDfZ3ZPCnt0HlNCHZd7sGq5G86+wo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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