SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67e94c2be78ec4d87c2325f48e78e9c18b193cc764adad8263ad8b8d7a56d8dc' 
  AND token = '3gHZEoBvgPbOqZb3gq07GtSweAVrCBF4z0Cm4yxFCm4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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