SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37663e5f91fb6f31423e5003b68aab196f89646f9ad78bc6adfdce24f287f80f' 
  AND token = '5xsRERu+wk9q/h2OwVXun1bXImaxil40Z0OPv0SZEJg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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