SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dafdd933972d02d6c84a8ad679603678887c486dee4896a76b88217fd60c0261' 
  AND token = 'stwCuInayc8qBV0q9UOHqWaebMIrFj1QcvnPKghNVYk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}