SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc0b581b3083b76a3da4718eb53e7ddf991f746051038a992e486527fd10e70f' 
  AND token = 'CS2z5uLNAz2AUc0T6aJ1ayZh5rvFs8nKRBvuMoP7LMk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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