SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '806606955113f09704bb6218485df972997179eb7be9d50a595feb04d33f4d8c' 
  AND token = '+zYOrxQe8gOGOwkEi6fjXP5vEGxmRCA24xTMSEAvWEg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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