SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd6495f29462c392d5f141527dddb99e69ba7e20c049304bbe45ba963fa17d03' 
  AND token = '5X7vvWg+R4hYsU39BCUBnHCcjQZ8p4Z8nFNZvlZcX90=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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