SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84b73d89087121410bde83bf3ee16d2d47647a9f167a17b715669f0df04351eb' 
  AND token = '7yAxaXc0mTeGdPtSlTKrH0de0yUZrEqEPbpPKIzwIss=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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