SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9997fd7909a6106b9113ff814e912efbc8eb425505c34ceecebe1df69c890049' 
  AND token = 'c7ZIoBiyPD58gkSna2lSfcq5cMkUlFIQQhld5C5xNx8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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