SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7cfb3dbed339ce3fe64aece1716c6660d63dc8199531169ef43b9eaa09203c4b' 
  AND token = 'fUatfVntqX4PZ5TYDDB5EIY1CNsRbN/mqJaxClWuhMg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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